1. Field of the Invention
This invention relates to a high performance folded fin heat exchanger core of the type to be used in a heat sink that is coupled to the CPU of a computing device. The particular folded fin configuration of the heat exchanger core herein disclosed provides maximum surface area, efficient heat transfer, and optimal air flow so that the heat generated by the CPU can be effectively collected and exhausted to the atmosphere.
2. Background Art
Because of the heat that is generated by a central processing unit (CPU) common to personal computers, and the like, and the deleterious effects that may result as a consequence thereof, it is customary to couple a heat sink to the CPU by which the heat generated by the CPU is exhausted to the atmosphere. In fact, as operating speeds continue to increase, the CPU""s and their support chips generate increasingly larger amounts of heat. In general, the core of the heat sink consists of a series of thick (e.g. extruded aluminum) heat conducting fins. A fan is positioned at an air intake end of the core to blow air over the fins by which the heat is collected by the fins is exhausted to the atmosphere at an output end of the core.
In the typical heat sink, a relatively long linear air flow path extends between the air intake and output ends of the heat exchanger core. Because of this linear airflow path having the intake and output ends lying opposite one another, it has proven to be difficult to increase the heat conductive surface area of the core without also significantly increasing the size, material consumption and cost thereof. As will be known to those skilled in the art, heat sinks having heat exchanger cores with long linear air flow paths and small heat collecting surface areas are characterized by reduced performance and efficiency. Moreover, because the extruded heat conducting fins are thick, the number of fins that can be accommodated by a heat sink while meeting PC requirements is reduced.
Heat exchanger cores having the aforementioned linear flow path are known to experience a relatively high head pressure at the intake end and a pressure drop between the opposing intake and output ends. To overcome these pressure concerns and maintain a sufficient volume of air flowing through the heat exchanger core, an air delivery system containing air transport conduits is often employed to carry high pressure air from the fan to the air intake end of the core. Such an air delivery system typically consumes space and increases cost and, in some cases, raises the head pressure at the air intake end which may adversely affect the flow rate.
Therefore, what would be desirable is a heat sink for a CPU that contains an efficient heat exchanger core having maximized surface area and minimized space consumption and a relatively short, non-linear air flow path that can accommodate a suitable fan without requiring an intermediate space consuming air delivery system so as to avoid an increase in the head pressure at the air intake end of the core and a reduction in the flow rate through the core.
Examples of known heat sinks to be coupled to a CPU to dissipate the heat that is generated thereby are available by referring to the following United States patents:
A heat sink is disclosed herein of the type to be coupled to the CPU of a computing device so that the heat generated by the CPU can be effectively and efficiently collected by a high performance folded fin heat exchanger core and exhausted to the atmosphere. Each heat conductive fin of the heat exchanger core is folded to include a front face and a rear face that are spaced from one another and squeezed together at the bottom ends to establish a triangular primary air exhaust cavity. The primary air exhaust cavity runs laterally through the interior of the folded heat conductive fin. As an important detail of this invention, the top of each folded fin is open to create a vertically extending air intake opening which communicates at the interior of the fin with the laterally extending air exhaust cavity. Thus, it may be appreciated that the vertically extending air intake opening and the laterally extending air exhaust cavity are aligned at 90 degrees relative to one another to establish a perpendicular air flow path that runs from the air intake end at the top to the output end at opposite sides of the fin.
An opening is cut into the front face of the fin, and the cut out surface is bent rearwardly along a fold line towards the rear face to create an inner air blade that functions as an air splitter. More particularly, a first portion of the intake air supply is blown downwardly through the vertically extending air intake opening and outwardly from opposite sides of the folded fin via the laterally extending primary exhaust cavity. The remaining portion of the air intake supply is blown downwardly through the air intake opening and into contact with the rearwardly bent inner air blade. The inner air blade splits the intake air supply and diverts the remaining portion thereof into a triangular supplemental air exhaust cavity via the opening that is cut into the front face of the fin to form the inner air blade. The supplemental air exhaust cavity is established between the front face of a first heat conductive fin and the rear face of an adjacent fin.
In this regard, the heat exchanger core for the heat sink of this invention includes a plurality of the aforementioned heat conductive folded fins arranged face-to-face one another, such that generally upper and lower primary and supplemental air exhaust cavities extend laterally through successive pairs of fins. By virtue of the foregoing, the heat exchanger core is characterized by both optimal air flow and about twice the material and heat conductive surface area relative to conventional heat exchanger cores, whereby the thermal characteristics and efficiency of the heat sink is maximized. In the assembled heat sink configuration, a suitable (e.g. muffin) fan is attached to the top of the heat exchanger core so as to blow the intake air supply downwardly into the vertically extending air intake openings of the plurality of face-to-face aligned heat conductive fins. The CPU is coupled to the bottom of the heat exchanger core so that the heat generated by the CPU can be exhausted from opposite sides of the core to the atmosphere via the laterally extending primary and supplemental air exhaust cavities.